Now Harrison tells the Kscope Podcast: “If I’ve learned anything from Robert Fripp, it’s that you need a good big idea.”

The drummer, along with arranger Laurence Cottle, came up with the concept of adding to their chosen tracks with material from other Porcupine Tree material.

“It’s good practice, especially when you have a great arranger, to bring in themes from other songs,” Harrison says. “I had a whole list of really good riffs in other songs that we could steal. Laurence could work in any riff from any other song, in any other key in any other time signature, into any song we were working on.”

He adds: “Porcupine Tree songs have atmosphere. You need to find a good amount of melody and harmony.”

And he’s keen to avoid strict genre labels for Cheating The Polygraph. “Although this is jazz to some people, prog to some people, big band to some people – it’s kind of not to me,” he says. “It’s just my life in music.

“I’ve played a lot of different styles, and my favourite genre is good music. I guess all I’m asking is that you just listen to it.”